The investigation, opened on Friday, will be led by French consumer fraud watchdog DGCCRF, part of the economy ministry, the source said.
Apple acknowledged last month that it takes some measures to reduce power demands – which can have the effect of slowing the processor – in some older iPhone models when a phone’s battery is having trouble supplying the peak current that the processor demands.
The French watchdog’s preliminary investigation could take months, and depending on its findings, the case could be dropped or handed to a judge for an in-depth investigation.
Under French law, companies risk fines of up to 5% of their annual sales for deliberately shortening the life of their products to spur demand to replace them.
An Apple spokeswoman in the United States declined to comment on the French investigation, pointing to a 28th December statement in which the company apologised over its handling of the battery issue and said it would never do anything to intentionally shorten the life of any Apple product.
An Apple spokesman in France could not immediately be reached for comment.
A French consumer association called “HOP” – standing for “Stop Planned Obsolescence” – filed a legal complaint against Apple.
Apple already faces lawsuits in the US over accusations of defrauding iPhone users by slowing down devices without warning to compensate for poor battery performance.
Apple also said on 28th December it was slashing prices for battery replacements and would change its software to show users whether their phone battery is good.